Mold for hollow castings and method of forming the same.



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MOLD FOR HOLLOW CASINGS MD METHOD 0F FORWHNG HE S/WHEv MERSFELDER A APPLSCATIUN FHAD JULY 23 l191?.

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MOLD FUR HOLLOW CASTINGS AND METHOD OFFORVIING THE SAME APPUCATION FILED JULY Z3 191i Patented May 2, 1918.

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Snecillcation of Letters Patent. Patented Ilimi.

npplicaticniled .Tilly 23, i917. ISerial No, 182,171.

Be 'itlrnownthatf-We, WILLIAM "L. Minn'- A'noLPH F. RAD-Kn, both citizens Aoit-the United States of Ameri'oa' both re- -'o sidingA at' Detroit,- inthe county offfl/vaynev .aiid;Statef ofg'Michigan, have invented certain-new'- and useful Improvements in Molds .o'r'llollow Castings and Methods of Form# j'.Q ing-ytheSanid 'of which theiollowing is a4 10 speciiication, f reference being had ltherein tothe-'accompanyingdrawings.

, The invention relates to th artof casting 'hollow articles and is morel particularly. de-

:per centuof'loss in castingsincident to the rnetlmds, heretofore ernployed'- and also 'to the method j oitI forming the' mold. `2f0 "lFo I this .end thel invention. comprises,y first, t" thenovel"construction and method of'form.

1. fseinblingthis vcore with the other parts o'i..

V 'showing successiw'fe step'sf in the, V.foi-mining y ."of thel core ."f l `ig. 6 is a'cross-section:Showing'the manner otformingfthe dragsection .of the mold Figs is a similar vien showing the inanner-fofforniing. the-cheek'seotion; ";fFig. 8 'isa similar. View showing the .man-- :herI ojfflorming the cope section gj i rig.- 9- is e Section @magnete-:connette .rated jin F' gs. 10` and l1 is'- a1 .holloivlring 1i-seiny 'furnace construction, comprising ,central dome-shaped j aortion", A, aj.' suriofunding' holloi'v section aai.: ber-111? .diamtriall@@pressentiest signedfor use inpgthefforming of hollow 'castV 'rings .for furnace :construction-:rt'isf. 1^.'...the'ob3ect of lthe.invention-to avoid Va large.

B eholor'iradiel. s. .onnecting .seotion.- .Gil .and Fa" radial brace' such' castings are formed in two sections i low' 'radial connecting section C. Usually" langed and bolted' to each other; but Where yan integral construction is employed it is usual to cast the same by the use of a baked core. n account of the relatively large causes Jfracture. or lossof castings formed by this method diameter of the hollow ring and slight thick- Aness of the Walls. thereoi1 it is diiicult to successfully cast the member, as the contractionY ofthe metal in cooling frequently is .very high and the cost is therefore corl respondingly ygreat.v With the present method this loss is almost entirely eliminated core` for' the-baked-core and byV providing thorough ventilation for this core so as to 'ermit 4escape of. steam land gases. -lt is, .owever, nec.essary to provide soi'ne means ofsu'pporting the core Within the outer mold, and a green-sand core .is not .fsuilciently strong to yloe successfully-supported from a .limited bearing; asis the practice with baked cores. This dilliculty is 'overcome by the einployrnent'of asupporting base for the core ytt'ornied y"of baked. sand, upon 4which the green-sandv core is mounted and supportedv Withinthe mold cavity..` Provision is also made for 'rei-I lforcing -the greenfsand core so that the: upward s tressdueto the flota- .tion o fthcmolten metal may be vsuccessfully resisted. 'l f cro'ss-sectionf corresponding to .that of' vthe ring-B. v 'ln this'boX islirst placed a series :off c hill'sor4 small metal plates E, which `are distributed around' the ring and :conform to the .cross#sectionl of 'thelower portion of the box. ...Over 'these .chills a 'perforated vent Ypipev is lpla :ed,'r.:this beingformed. inL segin'ents' Gr G Qetc.,-=having theirend formed- .for engagement With each other and at o ne point in the'cir'cle' V the'pipe i's connected yvith f the radially, voutwardly extending pipe H.

Metallic posts onstandsjl 'are then placed: uponthe chills lf, these being forked atl ha'veffaftlat bearing 'l2 and4 if desired the 'postsimay 'abe held in' Arelative position Aby' As a result the percentage 4 lby the substitution of a yieldable greensand I'n-detailithemethod of-formingthe mold 'Y to embracethe sections of the vent pipes' The-Supper ends of these.- postsf'l f Figs l and 2,the green-sand is illed in, is

tamped and struck-od flush with the faces of the enlarged bearing I2, as shown in F ig. 3. An annular baked sand core K is 4then placed in the upper portion of the' core-box and the latter is reversed in position and then removed from the core. This .Will leave the green-sand core supported upon a baked sand base, as shown in Figo.

In forming the outer mold the drag section L is first formed by a suitable `paptern M, and anchors N are embedded therein so as to expose chill faces N', preferably in positions of registration with the posts I.

The core 0 for the dome A is formed in the drag and the face O thereof is complethe cheek section on the line P2 the cope section S is placed in position and sand filled therein to unite with the sand in the segmental spaces. The cope section is provided, as is usual, With cross-bars 'S for holding the sand in suspension therein and b rods T are placed across the bars S so as to -register with the posts or stands I of vthe core. The rodsR each have their upper ends locked to the cross-bars S by Wedge members R, after which the cope may be drawn oi", the segmental plates Q supporting the depending sections thereof.

The sections are then separated, the pat,

tern removed and the core placed upon the drag, being supported by chaplets U resting upon the chill lugs N and engaging the baked sand portion K of the core. Chaplets V are also placed in contact with the chill I plates F at the top of the core in position to bear against lugs T on the bars S when the cope is in position. Thus after the cheek section and copesection are placed upon the drag the core will be supported therein and will'be securely anchored against any flotation pressure. This is due to the fact that the baked sand core K will resist the direct pressure of the molten metal in the mold cavity and from this section the stress will be transmitted through the posts or stands I to the chill plates F and froml the latterl through the chaplets V to the lugs T on the bars S. The vent pipe within the cor'cfis connected with a pipe IV passing through the cheek section and the mold is then ready for use.l f

It' will beunderstodthat in the casting insegno of the metalthe contraction of the same is permitted. as the green-sand core is yieldable and the steam and gases evolved by the heat are freely vented through the perforated pipe sections G G, etc., and connecting pipe W. As a consequence there is no stress eX- there are any portions of the mold cavity other than those in the cope which present down-facing surfaces these may be formed by baked sand sections, as indicated at X and X.

What We claim as our. invention is:

I. The method of forming molds for hollow castings, 'comprising the molding of a core section of green-sand, placing a, compiementar-y baked core section on top of said green-sand section, reversing, and removing from the core box and inserting in the cavity of the mold while supported on the baked section.

2. A core for hollow castings, comprising a baked base section, a green-sand 4section supported on and complementary to said ase section, and rigid reinforcements cm bedded in the green-sand section for carrying stresses therethrough.

3.- A core for hollowy castings, comprising a baked base section, a green-sand section supported upon and complementary to said baked base section, and vertical posts or stands embedded in said green-sand section resting upon said baked section and carrying stresses therefrom upward to the top ofA the core.

4. A core for hollow castings, comprising a. baked basesection, a green-sand section supported upon and complementary to said baked section, a post 0r stand resting on said baked section and embedded in said green-sand section, anda chill forming a portion of the molding faceresting on said post. v

-5. A core for hollow castings, comprising a baked b ase section, a greensand section supported upon and complementary to said baked section, a post resting upon said baked section embedding in said green-sand .tion carried by said post, and a chill sup- Nported on the upper end ofsaid post form-- ing a portion of the moldingface.

@COTS havin. a hreked hase 'portionnnd a section,a vent pipe insaidgreen-sand sec- Leeeoo complementary green-.sand portion support-l ed thereon, a post embedded in the green'- sand portion and supported on the baked section, a chill at; the upper end of said post forming a portion of-the molding face, an-

chors in the drag `and cope sections, andl chaplets between said anchors and the core for carrying stresses thereinto and through l said posts. v v

A7. A mold for hollow castings, comprising a drag section, a cheek section and a cope section having formed therein complemeni -tary portions of the mold cavity,v the drag and cope sections having anchors embedded therein anda core having a baked base seeded in said greenls'and seot1on,. avent' pipe embedded.' in the green-Sand ection-..posi

.tioned bysaid post, a chill 'at theupperend' ofv said post forming-a portionfof the mold;

ingV faenaA ehaplets. for supporting Ithe 'core Vupon the anchors in the dragsection, and,-

cha'plets betwcenfs'a-d ehill land anchor thel cope section .for resisting the'4 dotation" stress exerted upon'the core.

- n testimony whereof vlWe ax pour' signa-.- allures.

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